firmware/pwmled.c

   1 #include <avr/io.h>
   2
   3 #include "lights.h"
   4
   5 typedef struct {
   6         uint16_t target, pwm;
   7         int16_t err_sum;
   8         unsigned char mode, state;
   9         union {
  10                 unsigned char probe_steady, mode_changed;
  11         };
  12         uint16_t mode_pwm[N_PWMLED_MODES];
  13         int16_t err_sums[N_PWMLED_MODES];
  14         unsigned char modes_not_yet_stable;
  15 } pwmled_t;
  16
  17 pwmled_t pwmleds[N_PWMLEDS];
  18
  19 /*
  20  * Mode stabilization:
  21  * when changing brightness via pwmled_set_brightness() below,
  22  * we want to converge to the target value as fast as possible. Also,
  23  * we would like to somehow initialize the mode 3, which is used as
  24  * "mode 2 + other PWMLED on". So after the brightness is set,
  25  * we also set pwmleds[n].modes_not_yet_stable to MODE_STABILIZATION_TIME.
  26  * When modes_not_yet_stable is non-zero, we allow only mode 2 to be set
  27  * regardless of what is fed to pwmled_set_mode. We will then converge
  28  * to the target value of mode 2 only, and after MODE_STABILIZATION_TIME
  29  * ADC measurements, we copy the mode_pwm value to all other modes.
  30  * Only then it is allowed to set the other modes.
  31  */
  32 #define MODE_STABILIZATION_TIME (2*16)  // two seconds worth of measurements
  33
  34 #define PWMLED2_TESTING_WITH_350MA_LED
  35
  36 #define SENSE_MOHM      33      /* 0.033 Ohm */
  37 /*
  38  * Voltage in uV at ADC reading == 1 is 1100/gain/1024
  39  * ADC module returns sum of 1 << PWMLED_ADC_SHIFT measurements
  40  * Voltage in uV measured is current in mA * sense resistance in mOhm
  41  */
  42 #define MA_GAIN_TO_ADC(ma, gain) ((uint16_t) \
  43         ((uint32_t)(ma) \
  44         * (SENSE_MOHM) \
  45         * (1 << (PWMLED_ADC_SHIFT)) \
  46         * 1024 \
  47         / (1100000/(gain))))
  48
  49 static uint16_t adc_max[N_PWMLEDS] = {
  50 #ifdef TESTING_FW
  51         MA_GAIN_TO_ADC( 400, 20),
  52         MA_GAIN_TO_ADC(  30, 20),
  53         MA_GAIN_TO_ADC( 800,  1)
  54 #else
  55         MA_GAIN_TO_ADC( 900, 20),
  56         MA_GAIN_TO_ADC(  30, 20),
  57         MA_GAIN_TO_ADC(2500,  1)
  58 #endif
  59 };
  60
  61 static uint16_t adc_targets_0[] = {
  62         MA_GAIN_TO_ADC(  50, 20),
  63         MA_GAIN_TO_ADC(  80, 20),
  64         MA_GAIN_TO_ADC( 160, 20),
  65         MA_GAIN_TO_ADC( 350, 20),
  66 };
  67
  68 static uint16_t adc_targets_1[] = {
  69         MA_GAIN_TO_ADC(   5, 20),
  70         MA_GAIN_TO_ADC(  10, 20),
  71         MA_GAIN_TO_ADC(  20, 20),
  72 };
  73
  74 static uint16_t adc_targets_2[] = {
  75 #ifdef TESTING_FW
  76         MA_GAIN_TO_ADC( 120,  1),
  77         MA_GAIN_TO_ADC( 160,  1),
  78         MA_GAIN_TO_ADC( 240,  1),
  79         MA_GAIN_TO_ADC( 320,  1),
  80         MA_GAIN_TO_ADC( 460,  1),
  81 #else
  82         MA_GAIN_TO_ADC( 150,  1),
  83         MA_GAIN_TO_ADC( 300,  1),
  84         MA_GAIN_TO_ADC( 500,  1),
  85         MA_GAIN_TO_ADC( 700,  1),
  86         MA_GAIN_TO_ADC(1500,  1),
  87 #endif
  88 };
  89
  90 static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES];
  91
  92 #define ST_DISABLED 0
  93 #define ST_OFF      1
  94 #define ST_PROBING  2
  95 #define ST_ON       3
  96 // The above are constructed so that the following work:
  97 #define ST_IS_ON(s)     ((s) & 0x02)
  98 #define ST_CAN_SET_MODE(s)      ((s) & 0x01)
  99
 100 void init_pwmled()
 101 {
 102         unsigned char i, j;
 103
 104         for (i = 0; i < N_PWMLEDS; i++) {
 105                 pwmled_t *led = pwmleds + i;
 106                 led->err_sum = 0;
 107                 led->target = adc_vals[i*N_PWMLED_MODES];
 108                 led->mode = 1;
 109                 led->probe_steady = 0;
 110                 led->state = ST_OFF;
 111                 led->pwm = 1;
 112                 pwm_set(i, led->pwm);
 113
 114                 for (j = 0; j < N_PWMLED_MODES; j++) {
 115                         led->mode_pwm[j] = 0;
 116                         led->err_sums[j] = 0;
 117                 }
 118         }
 119
 120         pwmled_set_brightness(PWMLED_BRIGHTNESS(0, 2, 1, 0, 2));
 121 }
 122
 123 void pwmled_set_mode(unsigned char n, unsigned char mode)
 124 {
 125         pwmled_t *led = pwmleds + n;
 126
 127         if (!ST_CAN_SET_MODE(led->state))
 128                 return;
 129
 130         if (led->mode) { // save the previous state
 131                 led->mode_pwm[led->mode - 1] = led->pwm;
 132                 led->err_sums[led->mode - 1] = led->err_sum;
 133         }
 134
 135         led->mode = mode;
 136
 137         if (mode > 0 && mode <= N_PWMLED_MODES) {
 138                 if (led->modes_not_yet_stable) // only mode 2 when !stable
 139                         mode = 2;
 140                 led->target = adc_vals[n*N_PWMLED_MODES + mode - 1];
 141                 led->state = ST_ON;
 142                 led->pwm = led->mode_pwm[mode - 1];
 143                 led->err_sum = led->err_sums[mode - 1];
 144                 led->mode_changed = 1;
 145                 pwm_set(n, led->pwm);
 146         } else {
 147                 led->state = ST_OFF;
 148                 pwm_off(n);
 149         }
 150 }
 151
 152 #define CHECK_BRIGHTNESS(var, expr, array) \
 153         do { \
 154                 (var) = (expr); \
 155                 if ((var) >= sizeof(array)/sizeof(array[0])) \
 156                         (var) = sizeof(array)/sizeof(array[0]) - 1; \
 157         } while (0)
 158
 159 void pwmled_set_brightness(uint16_t brightness)
 160 {
 161         unsigned char i;
 162
 163         CHECK_BRIGHTNESS(i, brightness & 0x7, adc_targets_0);
 164         adc_vals[0] = adc_targets_0[i];
 165         CHECK_BRIGHTNESS(i, (brightness >> 3) & 0x7, adc_targets_0);
 166         if (adc_vals[1] != adc_targets_0[i]) {
 167                 adc_vals[1] = adc_targets_0[i];
 168                 pwmleds[0].modes_not_yet_stable = MODE_STABILIZATION_TIME;
 169         }
 170         adc_vals[2] = adc_vals[1];
 171
 172         CHECK_BRIGHTNESS(i, (brightness >> 6) & 0x7, adc_targets_1);
 173         // we use only one mode, so no modes_not_yet_stable handling here
 174         adc_vals[3] = adc_targets_1[i];
 175         adc_vals[4] = adc_vals[3];
 176         adc_vals[5] = adc_vals[3];
 177
 178         CHECK_BRIGHTNESS(i, (brightness >> 9) & 0x7, adc_targets_2);
 179         adc_vals[6] = adc_targets_2[i];
 180         CHECK_BRIGHTNESS(i, (brightness >> 12) & 0x7, adc_targets_2);
 181         if (adc_vals[7] != adc_targets_2[i]) {
 182                 adc_vals[7] = adc_targets_2[i];
 183                 pwmleds[2].modes_not_yet_stable = MODE_STABILIZATION_TIME;
 184         }
 185         adc_vals[8] = adc_vals[7];
 186
 187         for (i = 0; i < N_PWMLEDS; i++) {
 188                 pwmleds[i].err_sum = 0;
 189                 pwmled_set_mode(i, pwmleds[i].mode);
 190         }
 191 }
 192
 193 #define PWMLED_PROBE_STEADY_COUNT 10
 194
 195 static inline unsigned char pwmled_probed_ok(unsigned char n, uint16_t old_pwm)
 196 {
 197         pwmled_t *led = pwmleds + n;
 198
 199         if (led->pwm == old_pwm) {
 200                 if (led->probe_steady < PWMLED_PROBE_STEADY_COUNT)
 201                         led->probe_steady++;
 202         } else {
 203                 led->probe_steady = 0;
 204         }
 205
 206         if (led->probe_steady < PWMLED_PROBE_STEADY_COUNT
 207                 && old_pwm <= led->pwm)
 208                 return 0;
 209
 210         // probed OK
 211         led->mode_pwm[led->mode - 1] = led->pwm;
 212         led->err_sums[led->mode - 1] = 0;
 213
 214         // next mode to probe?
 215         if (led->mode < N_PWMLED_MODES) {
 216                 led->probe_steady = 0;
 217                 led->err_sum = 0;
 218
 219                 led->mode++;
 220                 led->target = adc_vals[n*N_PWMLED_MODES+led->mode-1];
 221
 222                 return 0;
 223         } else {
 224                 unsigned char i;
 225
 226                 led->state = ST_OFF;
 227                 pwm_off(n);
 228
 229                 log_byte(0xF0);
 230                 log_byte(n);
 231                 log_word(jiffies);
 232
 233                 for (i = 0; i < N_PWMLED_MODES; i++)
 234                         log_word(led->mode_pwm[i]);
 235
 236                 log_flush();
 237
 238                 pattern_reload();
 239
 240                 return 1;
 241         }
 242 }
 243
 244 static inline void pwmled_err(unsigned char n)
 245 {
 246         pwmleds[n].state = ST_DISABLED;
 247         pwm_off(n);
 248
 249         log_byte(0xF1);
 250         log_byte(n);
 251         log_word(jiffies);
 252         log_flush();
 253
 254         switch (n) {
 255         case 0: err_flags.err_pwmled0 = 1; break;
 256         case 1: err_flags.err_pwmled1 = 1; break;
 257         case 2: err_flags.err_pwmled2 = 1; break;
 258         }
 259 }
 260
 261
 262 void pwmled_adc(unsigned char n, uint16_t adcval)
 263 {
 264         pwmled_t *led = pwmleds + n;
 265         uint16_t old_pwm;
 266         int32_t sum;
 267         unsigned char shift;
 268
 269         if (!ST_IS_ON(led->state))
 270                 return;
 271
 272         if (led->state == ST_ON && led->mode_changed) {
 273                 led->mode_changed--;
 274                 return;
 275         }
 276         // FIXME: test for maximum adcval value (adc_max[n])
 277
 278         old_pwm = led->pwm;
 279
 280         // shift = led->state == ST_PROBING ? 3 : 8;
 281         shift = 3;
 282
 283         sum = ((int32_t)led->pwm << shift)
 284                 + led->err_sum + led->target - adcval;
 285
 286         if (sum < 0)
 287                 sum = 0;
 288
 289         led->pwm = sum >> shift;
 290         sum -= led->pwm << shift;
 291         led->err_sum = sum;
 292
 293         if (led->pwm >= PWM_MAX
 294                 || (n == 1 && led->pwm > PWM_MAX/2 && adcval < 0x08)) {
 295                 pwmled_err(n);
 296                 return;
 297         }
 298
 299         if (led->state == ST_PROBING)
 300                 if (pwmled_probed_ok(n, old_pwm))
 301                         return;
 302
 303         if (led->modes_not_yet_stable) {
 304                 if (!--led->modes_not_yet_stable) {
 305                         // reached stability, copy mode 2 to mode 3 (-1)
 306                         led->mode_pwm[0] = led->pwm;
 307                         led->mode_pwm[2] = led->pwm;
 308                         led->err_sums[0] = 0;
 309                         led->err_sums[2] = 0;
 310                 }
 311         }
 312
 313         if (led->pwm == old_pwm)
 314                 return;
 315
 316         pwm_set(n, led->pwm);
 317 }
 318